Transplacental passage of WEHI-3 tumor viruses induce lymphomas in offspring suggesting that immunologic responses to them have not been elicited; adult BALB/c mice cannot reject these tumor-inducing viruses; these viruses are in some instances sequestered and/or produced within the bone matrix; demyelinization of spinal cord axons and the presence of virus in the spinal cord may be related phenomena in animals that develop the hind leg paralysis. Preliminary chemotherapeutic studies using Levamisole (Ortho). Latency periods of tumor development did not differ significantly from tumor injected controls.